- Lead
- 42,607
- Total
- 92,012
- vs nation
- D+47.8
Illinois 15th State Senate District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 54,810
- Total
- 102,376
- vs nation
- D+49.1
- Lead
- 55,848
- Total
- 101,288
- vs nation
- D+53.0
- Lead
- 50,194
- Total
- 93,629
- vs nation
- D+49.8
- Lead
- 57,586
- Total
- 99,431
- vs nation
- D+50.6
- Lead
- 44,354
- Total
- 92,727
- vs nation
- D+50.3
- Lead
- 40,355
- Total
- 81,986
- vs nation
- D+48.7
- Lead
- 37,908
- Total
- 74,461
- vs nation
- D+42.4
Key facts
- 2024 presidential margin
- D+46.3MIT Election Lab
- Population
- 217,0452024 5-year
- Population density
- 798 / sq mi2024 5-year · TIGER/Line
- Land area
- 272 sq miTIGER/Line
- Median household income
- $70,6412024 5-year
- White (non-Hispanic)
- 28.2%2024 5-year
- Black
- 54.3%2024 5-year
- Hispanic / Latino
- 12.9%2024 5-year
- Peak Democratic margin
- D+57.9 in 2008MIT Election Lab
- Peak Republican margin
- R+33.4 in 1920MIT Election Lab
- Most similar
- State Senate District 17, IL · twin score 99.4
presidential history
Party record book
Illinois 15th State Senate District · the strongest Democratic and Republican presidential performances recorded here, measured three ways.
1892–2024 (partial returns from 1876) · 38 presidential cycles · 38 with a vote-share denominator · 34 with a national benchmark
Highest vote share
Largest share of the presidential candidate vote cast here.
Democratic
Barack Obama2008
78.7%
78,288 votes · D+57.9 · modeled estimate
Runner-up · Barack Obama, 2012 · 76.3%
Republican
Warren G. Harding1920
64.9%
18,679 votes · R+33.4 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · 55.3%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Barack Obama2008
78,288votes
78.7% of the vote · D+57.9 · modeled estimate
Runner-up · Joe Biden, 2020 · 77,883 votes
Republican
Richard Nixon1972
38,162votes
43.6% of the vote · D+12.5 · modeled estimate
Runner-up · Dwight D. Eisenhower, 1956 · 38,064 votes
Best relative to the U.S.
This Place’s margin against the national margin in the same election — positive when it leaned toward the party more than the country did.
Democratic
Hillary Clinton2016
+53.0pts D vs U.S.
Place D+55.1 · U.S. D+2.1 · modeled estimate
Runner-up · Barack Obama, 2008 · +50.6 pts
Republican
Warren G. Harding1920
+7.2pts R vs U.S.
Place R+33.4 · U.S. R+26.2 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · +1.4 pts
Current officeholders
State legislative officeholder from OpenStates nightly current-legislator data.
Senate and governor results are in the Office selector at the top of this page.
U.S. House
Each row is a county-allocated estimate of U.S. House votes for this district — county returns apportioned onto its boundary, not precinct-counted. “Vote lead” is the estimated local lead here, not necessarily the winner of the full contest.
| Year | Vote lead | Democratic | Republican | Total |
|---|---|---|---|---|
| 2024 | D | 68.5%58,499 | 31.5%26,930 | 85,429 |
Illinois 15th State Senate District sits in the Upper Midwest. In 2024 it voted Democratic.
Across the recorded series it reached a Democratic high of 57.9 points in 2008 and a Republican high of 33.4 points in 1920. Between 2020 and 2024 the district moved 7.2 points toward the Republican candidate; the 2024 margin was 46.3 points.
A population of 217,045, a 28% non-Hispanic-white share, and a median household income of $70,641 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 17 and State Senate District 4.
The state-senate districts whose fingerprint — 2000–2024 trajectory, demographics, ancestry, religion — sits closest to this one, and why.
Twin score (0–100) = weighted cosine between tier-standardized fingerprints: presidential margins 2000–2024 with 12-yr trend and elasticity, ACS income, age, education, population and race, top reported ancestries, and religious adherence — chips name the closest-shared dimensions and the widest gap. Re-weight the groups in the twins explorer.
District research tools
Open the source-auditable district brief for electoral baseline, electorate, current-cycle coverage, geography, official dates, and methodology. Open campaign intelligence report → · Browse all comparisons →
Illinois 15th State Senate District. Akashic. https://akashic.app/sld-upper/17015/. Accessed May 20, 2026. License: CC BY 4.0.